Guanidinoacetate Methyltransferase (GAMT) Deficiency
What is GAMT deficiency?
Guanidinoacetate methyltransferase deficiency is a disorder that affects the brain and muscles. It is a very rare disorder, with only about 80 cases being recorded in medical literature.
What are the symptoms of GAMT deficiency?
There are severe neurological symptoms that characterize this disorder, including epilepsy, issues with speech development, intellectual disability, issues with communication and social interaction, and self-injurious behaviors. Affected individuals may also experience tremors and involuntary movements.
Muscle symptoms are also common. These include weak muscle tone and a delay in the development of motor skills. At times, people lose some motor skills that they already have.
What causes GAMT deficiency?
As the name suggests, this disorder is caused by a lack of the guanidinoacetate methyltransferase enzyme. This deficiency occurs because of a recessive mutation in the GAMT gene, which stops the production of creatine. Without enough creatine, many organs throughout the body experience a shortage.
How is GAMT deficiency diagnosed?
Urine and plasma tests are used to diagnose this disorder. Genetic testing and brain MRI spectroscopies may also be helpful in obtaining a diagnosis.
What are the treatments for GAMT deficiency?
Early treatment is very helpful in obtaining the best outcomes, and treatment consists of oral creatine monohydrate to replenish creatine levels. A special diet, L-ornithine supplementation, and sodium benzoate are all helpful as well.
A team of specialists is recommended to manage symptoms.